This script allows CJ to visit a pawn shop behind his house, where you can sell your weapons, because CJ don't need to get them back - there are a lot of weapons around SA. If you don't have the need money, and/or have needless weapons, you can use this feature.
There are some people in the shop, communicating and checking prices. Weapons have to be sold to the guy in a dark blue shirt, with a prostitute helper neear him. You can't sell fists, detonator and camera.
The prices:
Additional weapons (cane, flowers and more certain) - $50
Melee - $100
Grenades - $500
Pistols - $300
Shotguns - $1000
Machine guns - $800
AK47 and M4 - $2000
Rifles - $1000
Rockets, flamethrower, minigun - $3000
Spraycan, fire extinguisher, night vision goggles - $150
ENJOY